From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Thompson, David" Subject: Re: [PATCH] scripts: environment: Properly handle SIGINT. Date: Sat, 26 Mar 2016 14:33:16 -0400 Message-ID: References: <87pouhbd46.fsf@izanagi.i-did-not-set--mail-host-address--so-tickle-me> <871t6x14kq.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Return-path: Received: from eggs.gnu.org ([2001:4830:134:3::10]:43883) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ajt1R-0006Qg-S6 for guix-devel@gnu.org; Sat, 26 Mar 2016 14:33:18 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ajt1Q-0006Ld-Sz for guix-devel@gnu.org; Sat, 26 Mar 2016 14:33:17 -0400 Received: from mail-qk0-x230.google.com ([2607:f8b0:400d:c09::230]:34292) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ajt1Q-0006LX-Oe for guix-devel@gnu.org; Sat, 26 Mar 2016 14:33:16 -0400 Received: by mail-qk0-x230.google.com with SMTP id x64so23218312qkd.1 for ; Sat, 26 Mar 2016 11:33:16 -0700 (PDT) In-Reply-To: <871t6x14kq.fsf@gnu.org> List-Id: "Development of GNU Guix and the GNU System distribution." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guix-devel-bounces+gcggd-guix-devel=m.gmane.org@gnu.org Sender: guix-devel-bounces+gcggd-guix-devel=m.gmane.org@gnu.org To: =?UTF-8?Q?Ludovic_Court=C3=A8s?= Cc: guix-devel On Sat, Mar 26, 2016 at 2:23 PM, Ludovic Court=C3=A8s wrote: > David Thompson skribis: > >> Has anyone ever been really annoyed that C-c doesn't work in a bash >> shell spawned by 'guix environment'? Me too! And I finally got around >> to fixing it. I would like to get this in before 0.10.0 is released. > > Indeed, that=E2=80=99s annoyed me a few times. :-) (C-z does work thoug= h.) > >> From ec7994eec73d322386abbcd901da1b1d2f6f7733 Mon Sep 17 00:00:00 2001 >> From: David Thompson >> Date: Sat, 26 Mar 2016 08:45:08 -0400 >> Subject: [PATCH] scripts: environment: Properly handle SIGINT. >> >> Switching to execlp means that the process spawned in a container is PID >> 1, which obsoleted one of the 'guix environment --container' tests >> because the init process can't be killed in the usual manner. >> >> * guix/scripts/environment.scm (launch-environment/fork): New procedure. >> (launch-environment): Switch from system* to execlp. Add handler for >> SIGINT. >> (guix-environment): Use launch-environment/fork. > > Isn=E2=80=99t it enough to add the =E2=80=98sigaction=E2=80=99 call to fi= x the C-c issue? No, because system(3) states that "SIGINT and SIGQUIT will be ignored." > Now, it=E2=80=99s nice to be PID 1 instead of PID 2, but that seems to be= a > separate issue, no? Ideally, it would be a separate issue, if it weren't for the above-mentioned issue that makes 'system' not usable for our purposes. >> * tests/guix-environment-container.sh: Remove obsolete test. > > [...] > >> -if guix environment --bootstrap --container \ >> - --ad-hoc bootstrap-binaries -- kill -SEGV 2 >> -then false; >> -else >> - test $? -gt 127 >> -fi > > This test was added in light of . We want to > make sure we don=E2=80=99t lose that property. > > What happens exactly when a signal is sent to PID 1? I would expect > that its parent process, which is outside the container in a waitpid > call, would simply get its exit value in the normal way, and thus, > changing =E2=80=9C2=E2=80=9D to =E2=80=9C1=E2=80=9D in this test should d= o the trick. Am I na=C3=AFve? :-) The problem is that a process within the container cannot just kill PID 1 since its the init process and the kernel protects it, so changing "2" to "1" doesn't work. The exit status of the environment command is 0 in that case because PID 1 never received the signal and thus exits normally. I'll try to come up with a replacement test case, thanks for giving me the context in which it was added. (I should've used 'git blame' first.) - Dave